The Chev LS1 will do just fine for my Cobra shaped Hot Rod. About the only Ford bits in the whole car are the door locks.
If you want be stick with the replica theme put a Ford in it. However they only came out with the 260 and 289 Windsors or the 427 428 FE motor. Putting a 351W or a 385 series motor in is about as correct as my LS1.
The original AC ace had quite a variety of engines before the ford V8 was wedged into it and the cobra badge stuck on. 6 cylinder engines from AC, Bristol and Ford have lurked under the shapely curves of the AC Ace. The original car hasn't seem to mind it's varied diet of engines over the years.
I'll judge each engine on it's own merrits and decide which one is best for my Car. There are a heap of engines which could qualify for the job of propelling a lightweight sports car along a twisty road at high speed all the while asaulting the senses with an antisocial exhaust note. I'm looking forward to seeing what one of our european brothers does when they get their hands on the BMW V10 from the M5 or a supercharged AMG Mercedes V12.
Cheers